A friend who runs Ubuntu 12.04, 64-bit, experienced screen rendering problems after an update. Symptoms include:
a) In Unity (3D), opening an application window in Desktop 1 opens it in Desktop 2. One cannot go to Desktops 2 or 4 (the 2 right-hand desktops) but one can drag it back to either desktops 1 or 3 (the two left-hand desktops).
b) In gnome-classic-fallback, no menus or any other items show up--it's simply a blank screen. It appears that the screen is rendered to be bigger than available screenspace. Trying to fix this by changing the screen resolution doesn't work.
c) In gnome3 shell, pressing the window key doesn't bring up the menus (again, probably of-screen)
d) Unity 2D works normally.
e) I installed Enlightenment window manager, and it works normally.
I would think that from the above this would be a Compiz problem, and that the thing to do would be to purge Compiz and re-install. But I thought that Gnome3 used metacity, not compiz.
Any replies or suggestions appreciated.
I went back to my friend's computer (finally!) and completely removed and re-installed compiz (along with unity aund ubuntu-desktop). That did not solve the problem. Instead, I found things worse, as I got a really ugly Ubuntu splash screen.
Then I just happened to look at the driver information. The Nvidia 304 driver was installed. I went and installed the latest updated version of the 319 driver (didn't work) then the recommended version of the 319 driver (didn't work) and finally I removed all the Nvidia drivers completely.
That worked, restoring the Ubuntu splash screen (well almost, it could use a higher resolution) and also the gnome and unity desktops.
a) I can't drag a window between workspaces in Unity; this suggests that the 3D acceleration for the Nouveau driver for this card (I can update that later) is lacking;
b) The maximum screen resolution is 1280 x 800, less than what it should be (I think 1440 x 900) and it detects the monitor as a "laptop" instead of a desktop monitor. This means I need to tweak a screen resolution setting.
c) There's also the problem with the splash screen resolution, but I've done that before, similar to this.
d) Grub will not come up by holding down the shift key; and that's a probably unrelated problem.